Loot Shanghai perhaps, causing misery (10)
I believe the answer is:
spoilsport
'misery' is the definition.
(I've seen this before)
'loot shanghai perhaps' is the wordplay.
'loot' becomes 'spoil' (I've seen this in another clue).
'shanghai perhaps' becomes 'sport' (I can't explain this - if you can you should give a lot more credence to this answer).
'spoil'+'sport'='SPOILSPORT'
'causing' is the link.
Can you help me to learn more?
(Other definitions for spoilsport that I've seen before include "Party pooper" , "One who ruins others' enjoyment" , "Killjoy" , "Person marring others' pleasure" , "misery" .)